[mythtv-users] Disk Access

[Craig Huff]

On Dec 11, 2007 11:37 AM, Stephen Robertson <stephengrobertson at gmail.com> wrote:
> I hope you will excuse what is hopefully a very simple question.  I've
> noticed an issue with my myth system(1 diskless frontend and 1 backend) if I
> am recording two dvb programs and watching one already recorded program.
> Mostly everything is fine however skipping/fast forwarding/rewinding is
> incredibly slow though it usually does resolve itself without falling over..
> Backend CPU and memory usage does not seem to show anything untoward and to
> be honest I'm not sure how to sensibly measure any disk access parameters.
> The disk for the recordings is used solely for storing recordings and is
> XFS.
>
Try executing the command "iostat 4 5".

This will report I/O statistics for five samples separated by four
seconds each.  The first
report will be cumulative statistics since the system was last booted.
 The man page will
explain what it tells you.  It is easy to have an I/O bound system
that doesn't show the
CPU burdened significantly, and this sounds like your problem.  Do you
have your
recordings on a different disk than the O/S and mysql database?
Hosting them all on the
same disk is frequently a cause of problems.

HTH.

Craig.